Avi Kivity wrote: > On 03/24/2010 06:40 PM, Joerg Roedel wrote: >> >>> Looks trivial to find a guest, less so with enumerating (still doable). >>> >> Not so trival and even more likely to break. Even it perf has the pid of >> the process and wants to find the directory it has to do: >> >> 1. Get the uid of the process >> 2. Find the username for the uid >> 3. Use the username to find the home-directory >> >> Steps 2. and 3. need nsswitch and/or pam access to get this information >> from whatever source the admin has configured. And depending on what the >> source is it may be temporarily unavailable causing nasty timeouts. In >> short, there are many weak parts in that chain making it more likely to >> break. >> > > It's true. If the kernel provides something, there are fewer things > that can break. But if your system is so broken that you can't resolve > uids, fix that before running perf. Must we design perf for that case? uid to username can fail when using chroots, or worse point to an incorrect location (and yes, I do use this) Sorry if this has been covered / discussion has moved on. Just catching up with the 500+ messages in my inbox.. Antoine > > After all, 'ls -l' will break under the same circumstances. It's hard > to imagine doing useful work when that doesn't work. > >> A kernel-based approach with /proc/<pid>/kvm does not have those issues >> (and to repeat myself, it is independent from the userspace being used). >> > > It has other issues, which are IMO more problematic. > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
